There are tons of other changes too, but the biggest thing is our gameplay. In Mists we were a burst oriented spec, now we are brought into arenas mainly for our utility and purges.

PvP Talents

Above are the general talents I use in arena. Some of them should be swapped depending on what comp you are playing, and what you are playing against.

Level 15:
Highly Recommended: Nature's Guardian

Nature's Guardian provides the best defensive boost for Enhance. Astral shift isn't bad, but the cooldown is too long for how long it lasts. Stone Bulwark is also a long CD and totem can be killed.

Level 30
Recommended: Windwalk Totem

Any 3 of these talents are viable. What is best will depend on many factors such as your play-style, the composition you're running, and what you're fighting against. Windwalk Totem is my general recommendation because Enhance suffers from mobility. Nearly any team you see in arena will slow or snare you in someway. Windwalk Totem is really nice for this situation. Windwalk Totem also helps a Beastmaster Hunter's stampede.Earthgrab is nice when you fight compositions that really need you to snare. An example is a death knight team without a freedom.Frozen Power has a similar logic to Earthgrab. It's also really good when you play with a druid to Frozen Power someone into a Solar Beam.

Level 45
Recommended: Totemic Projection or Call of the Elements

Call of the Elements is nice because it allows you to use double tremor and double freedom. I highly recommend Call of the Elements against any Priest or Warlock teams, and even Hunter + Warrior (Wyvern Sting + Warrior Fear). Totemic Projection is amazing to make your Capacitor Totem truly useful.

Level 60
Recommended: Echo of the Elements

Echo of the Elements lets you go almost "rotationless." You can pretty much hit Stormstrike / Lava Lash as much as you want when you account for the fact that you will be purging a ton in arena. Echo of the Elements procs extremely often especially when you get hit (it works on lightning shield.) Since NS no longer works with Hex this is by far the best talent imo.

Elemental Mastery is good for compositions that really rely on burst to win. However, it's purgable, and in the current WoD meta you do not want to use this against a ton of teams.

This entire tier is bad honestly, there really isn't a good talent here. This seems to give us the most on-demand damage, but it's closely followed by Elemental Blast. You can honestly pick any talent in this tree and you will hardly noticie the difference except for Primal. Primal would be the best talent if your opponents don't kill your totem that has ~26K HP (1-2 hits).

Level 100
Recommended: Elemental Fusion or Liquid Magma

Another relatively useless tier. Elemental Fusion is the best if you can't use Liquid Magma (it breaks CCs). Otherwise, Liquid Magma provides the most damage. Storm Elemental is really only good versus teams that has no knowledge of the fact they can just kill your totem in one to two hits.

Glyphs
Similar to talents Glyphs should be adjusted to what you play and what you play against. In general I keep Lightning Shield Glyph and Frostbrand Glyph as mandatory. The last one I swap out a lot.

Prime Glyphs:Lightning Shield - 10% damage reduction most of the time, incredibly useful for a squishy class like Enhance.Frostbrand Glyph - Applies a slow for you automatically, incredibly useful for a melee.Purge - Useful for really saving some of your globals, but if you get unlucky you can be stopping yourself from purging useful buffs. Use when you are not the only purge / dispeller on your team.Purging - Extremely useful for any teams you plan to purge spam. It allows you to heal a ton or use lightning bolts much more often.Capacitor - Useful for teams where you can keep Totemic Projection and you are afraid they may snipe your 5 second charge time totem.Hex - Reduces your hex cooldown by 10 seconds. Extremely effective against teams with no curse dispel or only one curse dispeller.Spirit Walk - Reduces your Spirit Walk CD by 25%. Nice for teams where you need to keep kiting or if you get heavily kited.Ghost Wolf - Makes you run at 100% even when you are slowed when using Ghost Wolf. Similar logic to Spirit Walk glyph but in a more consistent manner.

What rotation do you use in PvP?
There is no "specific" rotation in PvP. For Enhance Shamans it is exceptionally strange due to how important purging is and Echo proccing all the time.

Generally when you're not purging you want to use your 4-5 Maelstrom procs ASAP. Outside of that you want to use Stormstrike and Lava Lash. Keep Flame Shock up, keep Searing Totem or Fire Pet totem up. Unleash is a button you hit when you get kited or you have nothing else to do.

Macros / Keybindings?
Macros are largely personal preference. I prefer using @party1 and @arena1 kind of macros. Some players do it differently. Do what works for you!

As said with almost everything, Macros have a lot to do with personal preference. You can also use modifiers for different skills in your macros. Use these only as a general guideline and form your own macros!

Tips?
Stormstrike before you Ascendance in general. The Stormstrike in Ascendance does not share CD with it.
Make sure to Unleash before Elemental Blast or Lightning Bolt if you're using Unleashed Fury or Elemental Blast.
Keep in mind in WoD now we do not exactly do the most damage in the world. Pressure from Enhance is a stacking effect from purging, and somewhat decent consistent damage and a constant low CD ranged interrupt + other utilities. Don't be too discouraged when the damage on the scoreboard shows you're lower than everyone else! We also have probably one of the best constant heals in the game, so make sure you're using those procs.

This guide is written mainly for players new to playing retribution in arena / PvP.

What changed about Rets in 6.1?

1.) The main change is honestly the pacing of the game due to trinket buffs.

2.) Empowered seals was buffed, healing was increased and haste was also increased from the respective seals.

PvP Talents

In the talent picture I selected talents that I use as default in arena. Talents and Glyphs should be changed every arena match depending on what composition you're playing, what you're up against, and what strategy you and your opponent might execute.

Level 15:
Usual recommendation: Long Arm of the Law.

Why Long Arm of the Law? Well Judgement cooldown is incredibly short, so this sprint is almost on demand.

Level 30
For most compositions I recommend Fist of Justice.

Any 3 of these talents are viable. What is best will depend on many factors such as your play-style, the composition you're running, and what you're fighting against. Fist of Justice is an easy to use instant CC that allows your teammates to easily chain off of as well. Fist of Justice also increases your HOJ range which is very useful for a melee. The Blind talent will now be quite useful when you don't have Fear on your team. Remember, this Blind is like the Rogue Blind for DRs and not a disorient!

Level 45Selfless Healer is recommended for most cases. Sacred Shield for teams that will purge you a ton.

Having Selfless Healer is useful to get those fast and lower mana costing heals on yourself or your teammates.

Due to how Selfless Healer gets purged in 1 hit no matter the stacks, Sacred Shield is superior if you're fighting teams that are going to purge a lot.

Level 60
Recommended: Clemency or Unbreakable Spirit

Clemency, a previous patch made Hand of Sacrifice dispel magic effects. Clemency was already really strong for most scenarios since you can use freedom, sacrifice, and protection twice.

Hand of Purity is awesome for counter comping into DOT cleaves. Hand of Purity is to be used when you fight a DOT Cleave such as affliction warlock teams.

Unbreakable Spirit is particularly good when you know you're getting trained, especially against Caster Cleaves. The buff in 5.4 made this talent very strong, and I usually use this over the other 2 specs when fighting against double Caster compositions.

Level 75
Recommended: Holy Avenger

All 3 talents here are quite strong, but Holy Avenger usually performs best for burst which fits the current meta game with long CC chains to get kills. Holy Avenger also lines up with Avenging Wrath perfectly to use together for stacking CDs.

Final Verdict gives the most damage against targets that aren't cloth or leather without a fight, Empowered Seals could be better vs low armor targets and if you need to run or chase a fast target (Seal of Justice sprint).

Empowered Seals would also be the superior defensive talent due to it's kiting ability. I believe this last tier is a bit of preference between these 2 talents now and what comps you're playing and playing against. I recommend trying both and see what you prefer.

Glyphs
Most major glyphs are purely preference. Prime glyphs there are several choices with Templar's Verdict in my opinion almost always being mandatory since Ret is always a viable kill option. The only way you'd ever take this off is if you're 100% positive you will not get targeted.

Prime Glyphs:
Templar's Verdict (Necessary) - Now works on exorcism as well!
Burden of Guilt (It allows you to slow on your judgement now in 5.4! Highly recommended especially when you have no slow on your team.)
Double Jeopardy (The extra 20% burst is really insane at the moment, purposely judgeing a focus target then swapping back right before you Avenging Wrath is really useful)
Word of Glory (Extra damage for all those WOGs you do!)
Glyph of Freedom - It reduces CCs on any targets you freedom by 25%. This is an amazing Glyph that works on stuns, Sap and more.

Seal
Seal of Justice is the best seal to use if your team doesn't have a consistent slow.
Seal of Truth is the best damage seal, if your team has a slow such as playing with a Death Knight, this is the preferred seal.

Viable Ret Comps
Try it out yourself!

What rotation do you use in PvP?
There is no "specific" rotation in PvP.

Everything is situational. Keep note that our hardest hitting ability will be Final Verdict, which also clashes with Word of Glory as both takes holy power.

What macros does Ret have for PvP?
Most of Ret PvP Macros look like this:
/cast [target=party1] Word of Glory.
You can basically fit in 1-4 for 1, and Word of Glory with Sacrifice / Freedom / Hand of Protection and you'll have most of the Macros I have. I only have 1-2 for most of them, and 1-4 for WOG for 5s. 1-4 for everything was a bit too overwhelming for me. (Not Enough Buttons + Too Crazy lol)
There are people who simplifies this by using mouseover macros and such, all personal preference. Add #showtooltip to the start of these macros if you want to see it.
Some other general macros:
1.) Focus HOJ
/cast [target=focus] Hammer of Justice

As said with almost everything, Macros have a lot to do with personal preference. You can also use modifiers for different skills in your macros such as Repent. Use these only as a general guideline and form your own macros!

Gearing Ret for PvP
Get the PvP gear, and avoid Crit / Multistrike stats when choosing which piece to get. Make sure to get your 4PC bonus for the main pieces.

Trinkets
Unless you're human obviously you would use the trinket that removes all impairing effects.
For your second trinket, I recommend a Strength proc trinket. If you're human I recommend using an On-Use PvP trinket to replace the medallion. You want to use double PvP trinket now due to it giving bonus resilience which is HUGE. Rets are an extremely common train target.

General Arena Tips
Ret is a very strange spec, their place in arena is rather vague. We have good burst damage during wings, but outside of that we're a bit gimped. We have INSANE off heals and good support, but we're also incredibly easy to CC as a melee class which throws everything off.
As a ret pally, you always have to remember you ARE NOT a warrior. You need to watch your partners the entire game. Do not waste your extremely insane off heals, freedom, BOP, Sac. You are a support class that can burst once every 2 minutes! In an arena match my eyes are on my party screen the most.
If you are playing with a DK or Warrior or Rogue, be considerate about your freedom. You can cleanse most of your roots, and my death knight can kill people around 2 times faster than me, why would I freedom myself?